As terminal devices are spreading in popularity, almost everyone has a terminal device. Moreover, the usage of terminal devices in people's daily life, such as work, study, amusement and the like, has become increasingly popular. That is, the terminal device is becoming a necessity of people's life.
Generally, an antenna of the terminal device is adjusted under a certain environment. Under this certain environment, the performance of the antenna may be optimal. Under a normal environment, the performance of the antenna will not be much of a problem, however, during a harsh environment, such as rainy day, cloudy day, or being in valley, or while the terminal device is held by a hand, etc., the antenna may not be suitable for the harsh environment so that problems may occur, such as poor signals, call drop, offline and the like.